小球藻對酚降解現象之初步探討

A preliminary study on the phenolic degradation by Chlorella sp.

黃于珊(Yu-Shan Huang)

指導教授 ： 高思懷

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2015年)

https://doi.org/10.6846/TKU.2015.00500

摘要

酚化合物為許多工廠會使用到的原料之一，其排放的廢水中含有高濃度酚，具有高毒性及難分解性，可用物理、化學及生物等方式處理。但物理化學方法成本高，容易產生二次污染物，以生物處理最具有經濟性，更無有害副產物產生。而現今的污水處理方式也以生物處理中的活性污泥法為主，但在廢污水處理過程中會產生大量CO2、且國內污泥產量日益增加而最終處置場地有限。若以微藻做為處理方式，其具有處理污水中碳、氮、磷的去除以及降解廢水中有機污染物的能力，處理後的微藻更可作為燃料等其他用途。
本研究將小球藻於含酚培養基中進行培養，酚濃度為0~1000 mg/L，觀察藻體生長情形以及酚濃度變化，進而探討小球藻對酚的耐受程度、降解能力以及利用GC/MS檢測酚降解後所產生的中間產物，再利用生長動力學模式探討小球藻之比生長速率與基質間之關係。
研究結果發現，在酚濃度200 mg/L時可使小球藻達到最高比生長速率，而600 mg/L以上則開始對小球藻產生明顯抑制現象，當濃度為1000 mg/L時小球藻生物質量完全沒有增加，同時酚也幾乎沒有減少，而酚濃度100~300 mg/L可在48 ~ 84小時內完全去除，同時總有機碳去除率也有96~100 %。由GC/MS檢測結果顯示，推測酚經由間位裂解後進入三羧酸循環中。本研究利用Monod動力學模擬在100~400以及600~1000 mg/L時分為低濃度及高濃度兩段行計算，其R2值分別為0.8435及0.638，顯示在高濃度基質下會抑制小球藻生長，不適合使用Monod模式；而利用Haldane模式求得之R2值則分別為0.9527及0.9892，明顯優於Monod模式，較適合於本研究中模擬使用。

關鍵字

小球藻 ； 酚 ； 生物降解 ； 生長動力學

並列摘要

Phenolic compounds are commonly used in many industries, which discharge into wastewater with the characteristics of toxic and low biodegradability. Physical or chemical treatments are costly and easily generate secondary pollutants, while biological methods produce large amounts of waste sludge, which cost much during the final disposal. Microalgae have been proven to have the ability to remove the organic carbon, nitrogen, and phosphorous in the wastewater, and produce bioenergy simultaneously, nevertheless, the degradation ability and phenomenon on the phenolic compounds still not clear.
In this study, chlorella sp. was cultured in up to 1000 mg phenol /L contained culture media; subsequently, the growth rates of chlorella and residual phenol concentration were examined, and the extent of chlorella toleration was investigated, GC/MS analysis was executed to exam the intermediate products during the phenolic degradation. Finally, growth kinetic model was simulated to investigate the growth rate of chlorella.
The results indicated that 200 mg phenol /L initial concentration has the maximum chlorella growth rate, and 100–300 mg/L of phenol can be removed completely within 48–84 hours, the removal rate of total organic carbon was 96%–100%. Whereas exceeded 600 mg phenol/L, the growth of chlorella was inhibited, and at 1000 mg phenol /L of initial concentration, the growth of chlorella biomass and phenol degradation were stope. On the basis of the GC/MS results, phenol is inferred to have entered the tricarboxylic acid cycle following the meta-cleavage process. The simulation with Monod equation at 100–400 and 600–1000 mg phenol/L, the R2 were 0.84 and 0.64 respectively, it showed that, high concentration of phenol inhibits chlorella growth so the Monod equation was not applicable in this study. In contrast, the Haldane equation yielded R2 of 0.95 and 0.99 respectively, indicating that this equation was superior to the Monod equation and thus it can be applied in the simulation of this study.

並列關鍵字

Chlorella sp. ； Phenol ； Biodegradable ； Growth kinetics

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